China's official news agency warned Saturday it was no time to "make waves" in the disputed South China Sea after the US said it would shift the bulk of its naval fleet to the Pacific Ocean by 2020.

"It is advisable for some to refrain from muddying the waters and fishing therein," said Xinhua, referring to the sea, which is part of the Pacific and the subject of overlapping territorial claims.

China claims the sea in full, and it is also claimed in whole or part by Taiwan, Brunei, Vietnam, Malaysia and the Philippines.

"As regards the South China Sea tensions, it is some other claimants, whether emboldened by the United States' new posture or not, that sparked the fire and have been stoking the flames," said the agency.

It was Beijing's "genuine wish" to turn the South China Sea "into a sea of peace, friendship and cooperation," added Xinhua, in the commentary entitled "Not to make waves in South China Sea."

Pentagon chief Leon Panetta announced the decision to deploy more ships to the Pacific as part of a new strategic focus on Asia earlier Saturday at the annual Shangri-La Dialogue in Sinapore.

He said it was part of a "steady, deliberate" effort to bolster the US role in an area deemed vital to the United States' future, and insisted the switch in strategy was not a challenge to China.